<template>
  <div>
    <h1>App</h1>
    <h2>v3</h2>

    info.age <button @click="info.age++"> {{ info.age }}</button>
    <hr>
    age<button @click="age++">{{ age }}</button>
  </div>
</template>

<script setup>
import { reactive, toRef } from "vue";

const info = reactive({
  name: 'jack',
  age: 20,
  size: {
    w: 100,
    h: 200
  }
});
const age = toRef(info, 'age');//ref(20)



</script>